Writing is a practical necessity. Like every other skill it does improve with practice. So advising people who are not good at it to not do it is wrong.
You're talking about writing as communication (i.e. essaying); he's talking about writing as aesthetic expression (i.e. fiction and poetry writing.)
The difference between the two is the difference between talking and singing: everyone needs to learn to talk; not everyone should attempt to get in front of a microphone (however much they enjoy doing it in the shower.)
The difference between the two is the difference between talking and singing: everyone needs to learn to talk; not everyone should attempt to get in front of a microphone (however much they enjoy doing it in the shower.)